


milk

by supernormal



Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: Awkward Conversations, Blow Jobs, Breastfeeding, Cis Male Character, Dirty Talk, Hand Jobs, Lactation, M/M, Medical Kink, Mutual Masturbation, Praise Kink, Tenderness, cis male asagiri gen, fdjsfhjskdhfsdkjf senku caring about gen makes me doki doki, kinda sorta, male breast growth
Language: English
Status: Completed
Published: 2020-06-26
Updated: 2020-06-27
Packaged: 2021-03-04 07:08:48
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 5,660
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24919603
Author URL: https://archiveofourown.org/users/supernormal/pseuds/supernormal
Summary: Gen has some new "developments" that he wants Senku to investigate. Turns out there's more to them than meets the eye...
Relationships: Asagiri Gen/Ishigami Senkuu
Comments: 9
Kudos: 95





	1. first appointment

**Author's Note:**

> I like nursing and gen with titties, cis or trans

"Senku-chan, are you alone right now?"

"Yeah, what is it?"

"Something… happened… and, um… can you take a look at it?"

"What?"

Gen was leaning against the doorway to the lab, his arms crossed over his chest. He nervously glanced over his shoulder to make sure that no one else was around. "Can you promise not to laugh? or be weirded out?"

"Gen, at this point nothing can weird me out."

"Okay…"

He dropped his arms from his chest. Senku stepped closer.

"I don't see anything off."

"Well, it's probably because I'm wearing a bunch of layers, so…"

He shed his overcoat and untied the rope around his waist, hands trembling.

"Why are you shaking?"

"Because I'm stripping in front of you, idiot."

“Oh.”

He let the rope and the red piece of leather it was holding fall to the floor. He opened his yukata, exposing the stitched-up undergarment. The first thing Senku noticed was that… he had some new assets under there, to put it one way. And they were pretty big. If it weren't for the baggy clothing he wore, the new C-cups he possessed would be plainly apparent to anyone.

_"Oh."_

"They’ve kinda been… growing for the past few months but I didn't think I needed to tell anyone… But when I woke up this morning they felt really sore and kinda tight… I don't know how to describe it... And since you're the only person I trust here to know anything… can you… um… examine them? L-like just to make sure nothing's wrong."

"Sure.” He scratched the back of his neck. _This is awkward._

"Can you come sit down? It'll be easier."

Gen sat on one of the benches inside and Senku kneeled on the floor so that his face was level with his chest.

"Okay… well, first, I'll need you to take that off."

"Y-yeah."

Gen's face was the reddest Senku had ever seen. He brought his fingers up to the top of his undershirt and nervously began to undo the fasteners. Senku leaned forward to watch, eyes widened. He turned away. "Why're you staring? It's weird..."

Without thinking, Senku grabbed his shoulders and jerked him back towards him. "Uh, because I'm your doctor right now? Let me see," he demanded.

Gen gave him a frightened look but didn't say anything. He slouched over and once again crossed his bony arms over his chest in defense.

Senku pulled his hands away. "Oh, um, I'm sorry. I didn't mean to scare you. Uh, you can turn away if you want."

He rolled his eyes. "N-no, it's okay. You can watch. you'll have to look at some point, anyway."

"’Kay."

"Um, can you just be a little more gentle from now on, though?"

"Yeah. Of course."

Gen undid the last of the straps, but still held the two sides together.

"Okay… here it is…"

He opened the undershirt, revealing the breasts that had been growing all this time. They were pretty big. Senku facepalmed inwardly at all the times he had probably brushed against them under his clothes.

Normally, breasts didn’t interest him. At all. But seeing them on his best friend like this… Whew. He wanted to keep gawking but also didn't want to make the atmosphere even more awkward than it already was. He inhaled sharply. "Can you take it all the way off for me?"

"Mhm." He slid the undershirt off, leaving him only in his pants. Senku would be lying if he said he didn't think Gen was really, really, _really_ attractive right now. To be fair, he always was gorgeous, but when he’s sitting a foot away from him, with his brand new titties out kinda made him feel something. They looked tantalizingly soft, as if they were inviting him to grope them. An image flashed through his mind of him bending down to suck on those puffy pink nipples while Gen petted him and quietly praised him for being such a good little boy.

He momentarily shut his eyes to cast those sinful thoughts from his mind. _Why am I only thinking about this shit now of all times._

"Okay, so in order to look at them I'm going to have to touch them. That okay?"

"Do whatever."

He took a deep breath. “If you say so.”

He reached up, hovering his hands over his chest and looking up once last time for a nod of approval. After he received it he gently placed his palms over the mounds of flesh. They were remarkably soft. And warm. He wanted to squeeze them and knead them in his hands but _that. wouldn't. be. appropriate. right. now,_ he reminded himself.

“Okay, so,” he cleared his throat after experiencing a voice crack. “So, they seem normal so far. According to what I've read, at least.” That was his way of admitting he had never touched a titty in his life.

“Okay…” Gen still had a note of worry in his voice. “Do you know why this happened?”

“Um… My best bet is that it’s a hormonal thing. You should be fine. The treatment for them would take awhile to make right now but if you really want them gone I can make it a side project or something.”

“I see…” He looked away in shyness once again.

Senku stared down at his chest. The temptation was too much to handle. “Gen… there’s something I still want to check out. Just sit tight, okay?” He pinched both his nipples and harshly twisted them in his fingers, eyes wide. _I can feel his milk ducts,_ he thought.

Gen twitched and arched his back. ”Aah! Senku-chan! What are you doing? That feels—”

 _“Shh,”_ he interrupted, ”I’m trying to see something.”

His breathing quickened with excitement as he squeezed and massaged around his nipples. He looked up and saw Gen’s blushing, sweat-covered face. He was panting, too.

_He’s so gorgeous right now._

“Mmh!” Gen wrapped his arms around Senku for support and squeezed him tight. “Wait, _fuck…”_ he breathed. “K-keep going. I think something’s happening.”

Senku squeezed one of his nipples between his thumb and index finger and finally, a tiny white drop of liquid emerged.

“I knew it!” He exclaimed, straining to sound normal and not extremely horny. “You're lactating.”

Gen squirmed in his seat. “Oh… I mean I was kinda thinking, ‘what if,’ but I didn't expect it to actually happen…”

“There you go.” He coughed. “So…”

“So…” Gen repeated.

“If you want relief from all the soreness you're going to have to get rid of all this buildup somehow.”

“Okay.”

“And right now, the easiest way for that is…” Senku briefly indulged himself by squeezing both his tits in his palms, “Breastfeeding.”

Gen looked at him incredulously. “Okay. With who?”

Senku stood up and leaned his arm against the wall behind him, trapping him. “You already know who, smartass.”

Gen nervously laughed. “What? Are you gonna do it right now?”

“‘Course. You want relief, right?”

“Yeah…”

“Good. ‘Cause I wanna relieve you.”

Senku released him and sat back down next to him. He put his face close to his chest and looked up at him sweetly.

“What do you say?”

Gen put his hands on his shoulders. “Do it. Please.”

He smiled. “There we go.” He adjusted himself so that he waa reclined sideways on Gen’s lap and his face was comfortably close to his bosom. 

“Ready?”

“Sure.”

He took a deep breath, and then experimentally licked around his right areola while cupping his hand around the other. Gen shuddered, shakily exhaled, and reached his arm around his back to support him. Senku closed his eyes, took the hardened nipple in his mouth, and sucked.

_“Ohh!”_

The warm wetness of his mouth on his nipple was indescribable. Senku kept sucking harder and harder until the next drop came out. The taste was hard to describe but it was just a bit sweet, maybe flowery but that also could have been Gen’s own scent mixing with it. Senku closed his eyes and hummed in satisfaction.

“Senku-chan… j-just… Keep going…”

It was a little slow at first but once he worked his mouth on the nipple long enough it began to steadily trickle into his mouth. Gen pulled him closer and held his head in place with his hand.

“Ah… Don’t stop… I-I can feel it helping already…”

Senku opened his eyes and looked up. Gen was biting his lip, trying to stifle his moans. His face was flushed red.

He twisted the other nipple with his fingers while he took care of the first one in order to get it ready. He was managing to get quite a bit of milk out by now. He made sure to gulp down every last drop. Gen sighed with pleasure. “Senku-chan, Senku-chan... _nnh…_ What would I do without you…”

“Mhm.” He shut his eyes and hollowed his cheeks around his teat, eager to swallow the rest of it.

Gen cooed praise at him and affectionately ran his fingers through his hair. Something about this seemed to have woken up a sort of maternal instinct within him.

 _“Good boy, good boy._ Just like that, Senku-chan. So fucking good…”

Eventually, he released, making a wet sound as his lips departed from his areola. He leaned back and got a look at his face while he caught his breath. Gen’s face was flushed and he was panting as well. He wiped his mouth, smearing milk and saliva on the back of his hand. “How was that?”

“Incredible… I swear you can fix any problem,” he gasped.

“Well, good news.” Senku fondled his other breast in his hand. “We still got one more to go.” He moved his face to it and flicked his tongue at it while looking up at him flirtatiously. Gen squirmed in his seat, flustered.

 _“Oh,_ Senku-chan…!”

“I gotcha.” He delivered a sloppy kiss onto the point before taking it into his mouth. He sucked hard right off the bat this time, making Gen cover his mouth with his hand to stifle his whimpering. Senku made sure to moan into his chest while he worked his mouth because he knew the vibrations of his throat would drive him wild. And he was right. 

“S-Senku-chan! I-I… _nnh!”_

The taste and feeling of his warm milk as it flowed out of his teat and into Senku’s mouth was something he could get addicted to. Gen clinging onto him as if it were for dear life and moaning praise at him wasn't too bad, either. He closed his eyes and shut out everything in the world except for Gen— No nagging villagers, no petrification, no civilization to restore, no nothing. Just his mentalist and his sweet new pair of tits. Nursing from him was strangely relaxing. Maybe it was also Gen’s soothing voice and warm embrace that he didn't know he needed. Whatever the case, he wanted to do this more often. A lot more often.

He set a good pace of suckling and swallowing. Gen had seemed to learn to stop wiggling around so much and instead stay still and steadily hold his partner while he nursed. Gradually, the trickle died down and Senku could tell that he had driven all he had stored. He gave one last suck at his nipple before releasing for the last time. He sat up and wiped off his mouth.

Gen was panting, chest glistening with sweat and saliva. But, he was smiling. Senku smiled back and reached up to fix his messed-up bangs with his finger. He licked his lips. 

“Feel better?”

He tiredly nodded. Senku moved his hand down to brush the back of his index finger over the scar on his cheek.

“I’m glad. Though…” He pushed himself off his lap and sat up next to him again, leaning his weight on his shoulder as he murmured into his ear. “I don't think we’re done here yet.” He gestured down to Gen’s crotch, where his throbbing erection strained against his pants. “I can't let you go running off like this.”

“Mn…”

Senku confidently looped his arm around Gen’s shoulder to pull him close to him. “And look.” There was a sizable bulge in his tunic where his hard-on was. “I can't be going off like this either, right?”

He fidgeted in his seat, face redder than ever, thrilled at his advances. “Uh-huh…”

“So…” He palmed at Gen’s bulge. “How about we take care of each other now?”

“Yeah,” he breathed. “I really need that.”

“Mhm.” He slipped his fingers into the waistband of his pants. “Let’s pull these down first.” He slid them down just enough so that he had easy access to his cock. It was clear how turned on he was by how eagerly it sprang up the instant the white leather passed over the head. Precum was already beading up from the tip and trickling down the shaft.

“Theeere we go. But you know, Gen, I'm not gonna let you get away with not doing any work at all, right?”

Gen playfully sighed and rolled his eyes. “What do you want now, Senku-chan?”

Senku guided his wrist down to his crotch. “You're gonna do me, too.”

He licked his lips. “If that's the case… I don't think it will be that grueling at all.”

Senku chuckled and thumbed the tip of Gen’s cock. He pulled up the front of his skirt and pushed his fundoshi to the side so that his cock was exposed as well. It was harder than ever, sticking out far into the air. Gen confidently wrapped his hand around the shaft so that they both had their hands on each other's dicks.

“M’ready…”

Senku gave him a squeeze. “Me too.” He started off by slowly stroking up and down his length. Gen was once again squirming, unable to stay still and clearly already near the edge. It took him a few seconds to catch up with Senku and start stroking him as well. “Getting your nipples sucked really turns you on, huh?”

“Yeah,” he signed.

Senku groaned at the way Gen skillfully worked his hand around his cock. He got back at him by gripping him harder and jerking him off faster.

”Hah… How’s that?”

“Ah… Oh, Senku-chan!” he squealed.

A few unaccounted-for drops of milk were bubbling out of his nipples and crippling down his chest onto his abdomen. Senku noted how good a look this was for him. Shirt open, his pale, smooth chest wet with saliva, sweat, and his very own milk. He couldn't resist pausing to dip down and quickly lick them off because the thought of any of his lactation going to waste was kinda annoying.

“Ohhh! Senku-chaaan! Cumminggg!” Gen bucked his hips forward in shock as his semen abruptly spurted out of the tip, some hitting Senku in the face.

“Ah!” He realized what was happening and tightened his grip and pumped his hand as fast as he could to coax the rest out.

 _”Eaah!”_ He shut his eyes tight and spread his legs as wide as he could while his climax shook him to the core.

 _“Hah… Ah…_ That feel good?”

 _“Yes! Yes, oh my god!”_ He thrust his pelvis up in the air, supporting himself with his free hand. He moaned loudly as the last of his cum burst from his cock and made a mess on both himself and his partner.

“Nn…” He was trembling. “That was amazing…”

“Guess you really needed that too, huh?”

“Uh-huh…”

Even though Gen had been struggling to properly jerk him off while he was cumming Senku knew that he was about to climax himself. “Fuck Gen, don't stop,” he gasped. “Harder. M’almost there.” He laid his hand over Gen’s fist and guided it up and down to lead him to his orgasm.

_“Urgh…”_

The semen shot out of the tip, going high in the air and splattering all over himself. He groaned and trembled as all the pressure he built up finally got released.

_“Fuckfuckfuck—”_

He gripped the edge of his seat in ecstasy as Gen skillfully pumped his fist on his cock.

_”Gen…!”_

He watched in awe at the way Senku writhed in pleasure. Having such a powerful man cry his name during an orgasm he caused was definitely a privilege.

_“Senku-chan...”_

Eventually all of his cum was gone and he relaxed back in his seat, panting hard. He ran his fingers through his hair to try to get it to stand up straight again since it got messed up.

“Shit, it’s been so long since I’ve felt that good,” he sighed.

“Mm…”

Senku placed his hand on his thigh. “You're all better now, right? Chest feels better?”

“Yeah. It was seriously bad back then.”

“Good.” He scratched the back of his neck. “Well…” Gen watched as he stood up and retrieved a damp washcloth from the table. "Before you get dressed, lemme clean you up a bit, okay?” He gingerly wiped his torso and upper legs down with it. Gen shuddered at the sudden coldness. “Ah, sorry about that. I'll make sure the water’s warm next time, ‘kay?”

“Next time?”

He didn't look up as he continued to wipe him down. “Yeah. I want you to come back next time you're backed up. Or whenever you need any help.I just um…” He paused. “want to make sure you're happy and never in any pain. Or whatever. I don't know.” He tossed the washcloth back onto the counter and stood up. “So…”

Gen felt his heart race. It was only once in a blue moon that Senku would ever say some corny shit like that. He wished that he could have recorded it to play back again and again so he could relish in the warm, fuzzy feelings Senku had a tendency to give him.

He stood up as well and pulled up his pants, suddenly feeling a bit too embarrassed to look him in the face as well.

“Let me help you get dressed.” He picked up the red belt he wore and tied the white string around his waist to keep it secure for him. Gen put his coat back on and straightened it out for him, patting his shoulders when he was done. “I’ll send you off now. But remember to come back whenever it gets bad, okay? And I’ll set aside some time to make you some pasties and maybe a bra just in case so you don't mess up your clothes or have your nipples show through, or…”

Gen mostly tuned out whatever he was saying at this point to instead relish in the way Senku cared for him. “Yeah… uh-huh,” he nodded, not listening.

“...Did you get all that?” He brushed his shoulders off with his hands.

He tilted his head and gave him that signature smile. "Yes, of course, Senku-chan!”

“Okay. Well, if it starts to hurt again or whatever, don’t hesitate to come to me, okay? I'll do whatever I can to help.”

He straightened his back and playfully saluted him. “Got it! Bye-bye, Senku-chan!” He ducked out of the entrance and skipped away, sweetly waving back at him. Senku waved in return and retreated back to his lab. He picked up one jar before putting it down and rushing back to the door.

_Gotta drill that last bit into his head._

He stuck his head out the doorway and called out. “Oh, and don't put it off! It won't be good for you if you procrastinate on dealing with it!”

But it was too late. Gen had already frolicked off to god-knows where. He scoffed, shook his head, and went back to cleaning his beakers. He licked his lips, trying to get one last taste of his milk. He leaned against the doorway and sighed.

_He better come back soon._


	2. second appointment

**Summary for the Chapter:**

> *drops this in front of you and sprints away*

Gen stumbled into the lab and grabbed onto the material of the back of Senku's dress.

“Senku-chan…”

“What’s up?”

He slouched against his back, scrunching the fabric in his hand and burying his face in his shoulder. "Nnh, Senku-chan… I can feel it building up again… It hurts… Can you help me?"

“Oh.” He hurriedly put his stuff away. "Yeah." He closed the curtain over the door and ushered him to the back of the lab. “Can you undress for me?”

Gen took off his overcoat and untied the string around his waist. He used both hands to open the collar of his yukata up and partially slip it off so that it was draped around his lower arms. He undid the string of his undershirt, hands trembling just like the first time. The sides came apart, revealing his noticeably swollen breasts. Two light brown pasties concealed his nipples, a creation of Senku's to control any unwanted leakages.

“Aw, poor baby. You must be so uncomfortable.”

Gen whimpered and began to pick at one of the pasties with his thumbnail to remove it.

Senku clicked his tongue and pushed his wrist out of the way. “Don’t—Let me get it.”

He took the first one in his fingers and started to peel. Gen let out a strained moan. He clasped his hand over his mouth to stifle any other sounds he would accidentally make.

“Sensitive?”

He frantically nodded.

“You definitely would be, just look at you…” He peeled off the rest, causing his partner to twitch. He looked at the back of it and saw that it was damp with his milk. He shook his head.

“You waited way too long,” he sighed. “What did I tell you? Don't put it off.”

He cast his eyes down shamefully.“Sorry…”

Senku reassuringly caressed his cheek with his finger. “No, it's fine, just… I'll take care of you, okay?” He took him by the hand and led him to the bench.

“Sit down.”

After Gen was seated, Senku sat down on his lap, facing him sideways so that he had easy access to his chest. Gen closely embraced him, the emotional neediness associated with his condition kicking in.

Senku gingerly touched his fingers to one of his breasts. It was _engorged_ with milk. He squished the nipple a bit between his fingers, and a drop of milk emerged.

“A- _ah!_ Oh, Senku-chan! Please help me!”

 _“Shh,_ I got you, I got you,” he repeated. He cupped his breast in his hand and moved down to gently kiss it. “Ready?”

“Yes!”

He delivered one more messy kiss onto the nipple and then latched on to begin suckling. Gen sighed heavily in relief and held on tighter to him. Senku briefly flitted his eyes up to meet Gen’s and saw the desperation in his face.

_He really needed this._

He closed his eyes and sucked harder. The milk was starting to consistently trickle out into his mouth. He always made sure to swallow all of it while admiring the slightly sweet, creamy taste on his tongue. Gen squirmed in his seat, letting out a mixture of moans and gasps each time Senku latched harder.

_“Senku-chan, Senku-chan… Fuck… Feels so fucking good… I need you so much…”_

As usual, Senku made sure to swallow each drop that flowed into his mouth, treating his milk like the scarce, coveted fluid it was. It tasted just as delightful as it did the first time. It tasted like _Gen._

He licked up from the bottom of his breast up to the pink nipple to get the milk that had come out on its own, not daring to waste a single drop. Gen let out a strangled moan when Senku touched such a delicate spot.

There was a lot this time. Senku hummed in satisfaction, feeling it fill his stomach. If he could, he would have this as a meal every day. But alas, building this much up took at least a week. He made sure to savor each bit that hit his tongue; it was that precious.

When the trickle dried up, he let go, licking the extra milk off his lips. Gen adoringly pet his head. _“So good,”_ he whimpered.

“Mm… Next one.” He squeezed his other breast in his hand and wasted no time in latching onto it and sucking hard. Gen squeaked and trembled under him, overwhelmed at Senku’s _enthusiasm._

“Eee… Senku-chan!”

He furrowed his brow in concentration as he gulped down the liquid. He kept one hand cupped on his previous breast and the other on the current one, finding himself a bit addicted to their softness.

Gen cooed praise at him and carded his fingers through his hair in admiration, encouraging him to keep suckling from him. _“Good boy, good boy…_ Drink up, okay, Senku-chan? You're making me feel so good…”

Senku opened his eyes again and looked up. The manner in which he gazed at him, eyes dark and sharp, as he nursed made Gen’s heart want to burst out of his chest.

Senku squeezed his breast hard, eager to lap up as much milk as he could. The wet suckling noises and moans he made while he worked his nipple in his mouth turned Gen on to no end. Senku was _too sexy_ like this. He winced at his hardening cock throbbing in his pants. He wanted Senku to drink the milk he made down there, too. The mere thought of Senku on his knees sucking him off as tenderly as he did his breasts almost made him cum himself right there and then.

He progressively loosened his hold on him and then released, leaving Gen panting with his chest smeared all over with his saliva and milk.

Gen lovingly pet his head. “Oh… all done?”

“Not quite…” He reached down to palm at Gen’s bulge, earning a soft whine from him. "Look how hard you got.” He lifted Gen’s chin up with his finger. “How do you want me to take care of it today?"

He paused, biting his lip. “…I-I want you to suck me off.”

"Of course."

He got up off his lap and then kneeled on the floor before him. He fished a hair tie out of his bag and tied his unkempt hair back into a ponytail. 

Gen hummed and adoringly pet his head. "Senku-chan, you should put your hair up more often."

"No way. I only do it for special occasions,” he smirked.

He slid his pants down to his mid-thighs so that he could access his cock. It was rock hard and stood up tall when it was freed from the restrictive material.

“I swear, you're way bigger than I'd expect someone who looks like you to be,” Senku remarked.

Gen stamped his feet a little bit in anger. “Senku-chan! Stop being so mean!”

He chuckled. “Don't worry, I'm just messing with you a bit.” He stuck out his tongue and flicked it at the tip, which already had his precum leaking out.. “Tastes good. Every part of you is delicious.”

“Senku-chan…”

Senku reached down with one hand to fumble with his belt so he could free his own cock, making sure to keep his other hand around his shaft. “Shit, this got me horny as fuck, too.” He wrapped his hand around his own length and started striking it. “Mm… You know, I need this too.”

Gen sighed in delight at the sight of Senku below him showing off his hard cock. “Senku-chan, you're really giving me quite the view now…”

He sweetly grinned. “Gonna start now.” He kissed the head and then took it into his mouth. The inside was delightfully warm and wet and felt just as good as it did when it was on his teat.

He arched his back in pleasure. _“Oh~!_ Senku-chan! Already!” He grabbed a fistful of his hair to guide his head up and down as he sucked. “Look up at me, please?”

Senku gazed up at him with his sharp red eyes. He couldn't really smile right now but the corners of his eyes crinkled in amusement at his usage of the word _please._

“Don't take your eyes off me, okay, Senku-chan?”

He subtly nodded, sliding more of his length into his mouth and fondling his balls in his hand. Gen moaned and gently thrust his hips forward to encourage him. He gripped his hair tighter and pushed his head down to the base, admiring the way his note nestled in his half-black half-white pubic hair.

_“Ah… So goood…”_

Gaze still fixed on him, Senku began to steadily bob his head up and down his cock. He wrapped his hand around the base to stroke the free part whenever his mouth back came up to the tip, and was still jerking himself off down there.

“I love the way you service me…” He let go of his hair and instead caressed his cheek in deep affection.

_“Mm…”_

The lab was filled with the wet slurping noises of Senku’s mouth and Gen’s soft pants and moans.

He really had a hidden talent for cocksucking. It took every ounce of Gen's willpower not to cum right there and then as to not disappoint him. He could tell Senku was enjoying this as much as he was.

 _“Senku-chan, Senku-chan…”_ Gen would never in a million years get tired of repeating his beloved’s name like that. “You’re amazing, Senku-chan!”

Senku closed his eyes and took the whole cock into his mouth, the tip hitting the back of his throat.

He bucked his hips forward, almost making him gag. _“Ooh! Senku-chan! I—”_

 _“Mmm!”_ Senku sucked on it hard, making sure to keep his tongue moving in his mouth to add some extra stimulation.

_“Ghh, I can’t hold it—Ah!”_

Senku snapped his eyes open and gazed up at him once more, the smile in his eyes still clearly apparent.

He grabbed his head with both hands and pushed his head down onto his dick. Senku furrowed his brow and grasped his thighs with his hand for support. He was jerking himself off even faster, clearly turned on by Gen’s display of desperation.

“I… I’m gonna fucking cum!” He buckled over and groaned as his seed shot deep into Senku’s mouth. Senku pulled off and opened his mouth wide, gasping for air as Gen unloaded himself onto his tongue.

 _“Nngh, Senku-chan!”_ he cried. Senku jerked both himself and Gen off at the same time, taking care to keep Gen’s cock aimed into his mouth. He stuck his tongue out to better display the semen on it to Gen.

After the last dregs of his load were out, Senku put his tongue back in his mouth and smiled. He swallowed it all, gulping it down in an exaggerated manner to complete his little show.

Gen collapsed back into his seat, exhausted and panting.

 _“Wait… Gen… watch… about to cum too,”_ he strained. He quickly pumped his fist around his cock, out of breath but dying to cum. He kept his sight on Gen as his cum finally came out, splattering onto his chest and on the floor.

 _"Ah… ah…"_ It looked like he was pretty backed up too. He came a lot, making a big mess of himself and the floor under him.

His hand slowed down as he came down from his high still twitching and trembling. He slumped down, leaning on his hands behind him, legs spread and cum-smeared cock on display.

_"Fuuuck."_

Gen took a moment to compose himself before gesturing at Senku to climb back up onto the bench to join him. He slipped his skirt back down and then did so. Gen scooted close to him, basically squishing their bodies together. After taking a moment to allow both of them to catch their breath, he placed his hand on his thigh. “Hehe, Senku-chan, you really like my milk, don't you? Both kinds.”

Senku pulled his hair tie off and shook his head around to make his hair stand up again, kind of like a dog shaking itself off after a bath. “…Yeah.”

He touched his finger to his chin.“Well, uh, I might consider just letting it be and not trying to go back to how it was.”

Senku opened his mouth to respond but Gen continued to speak. “If you promise to keep taking care of me so faithfully, of course.”

“I do!” He cleared his throat. “I mean, I will. I won't let you down.” He was blushing hard.

Gen smiled ear-to-ear, cheeks reddening as well. “If you insist, Senku-chan!” As he got himself dressed again, Senku couldn't help but stare. The way he hummed while readjusting his coat on his shoulders was kind of enamoring. He couldn't help but lean in to quickly peck him on the lips.

“Senku-cha—!” Gen covered his mouth with his sleeve, but was still clearly beaming under it.

“Just… as a thanks for relying on me, I guess.”

Gen put his arm down and wordlessly pulled Senku in by his collar to kiss him back, longer and closer this time.

“As a thanks for taking care of me.”

“Oh, um… I see.” He was so stunned he couldn't really say much. He took a second to compose himself. “Um… Why don't you stay in here with me for a while today?”

“Sure! Whatcha up to?”

“Working on an improved engine for our generator. Wanna see?”

“I'd love to!”

Senku led him to the counter and Gen trotted after him, sleeves together in his trademark fashion. As Senku rambled the details at him like usual he noticed he felt a little warmer and giddier to have Gen by his side than usual. He pulled Gen to his side by his waist and kept on speaking like nothing happened. Gen also kept listening intently as if nothing had happened, and this was how it always was between them.

Senku eyed him from the side, catching a glimpse of his silky white fringe of hair and his oddly adorable smile. He quickly looked away after feeling his heart thumping in his chest.

And this is how it’s always supposed to be.

**Notes for the Chapter:**

> writing a 5.6k word fic about senku breastfeeding from gen is definitely one of the more autistic things i've done  
> 

**Author's Note:**

>   
>  started this fic like. Literally 9-10 months ago and I've been doing bits and pieces intermittently since then so if it's all over the place that's why LOL
> 
> The second chapter is almost done so I'll post that within the next few days


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